Flying helmets



y 1968 M. J. o. LOBELLE 3,383,706

- FLYING HELMETS Filed Nov. 4, 1966 5 Sheets-Sheet l lA/VE'IVTOR y 1,1968 M. J. o. LOBELLE 3,383,706

FLYING HELMETS Filed 1966 5 Sheets-Sheet 2 y 21, 1968 M. J. o. LOBELLE3,383,706

FLYING HELMETS Filed Nov. 4, 1966 5 Sheets-Sheet 3 y Manwn 6 [52% v cflzw i 147 TOR/Vi y;

United States Patent Ofice 3,383,706 Patented May 21, 1968 3,383,706FLYING HELMETS Marcel J. O. Lobelle, Slough, England, assignor to M. L.Aviation Company Limited, Slough, England, a British company Filed Nov.4, 1966, Ser. No. 592,166 Claims priority, application Great Britain,Nov. 9, 1965,

47,500/ 65 Claims. (Cl. 2--6) Some types of flying helmets are fittedwith a pivoted visor which when in the lowered position shields thewearers eyes from the sun. The visor also protects the wearers faceagainst blasts of air, for instance those which occur when he is ejectedfrom the aircraft by an injection seat. However in the event of ejectionin an emergency he may not have the time or opportunity to lower thevisor into the closed position, or he may even be unconscious.

According to the present invention a flying helmet of this type includesa lever responsive to G-forces pivoted to the visor about a generallyhorizontal axis and connected through a spring to the helmet, the springbeing anchored at each end at points which are so located in relation tothe visor and lever pivot points that a two stage overcentre mechanismis formed, operation through the first stage of which is brought aboutby manual lowering of the visor into the closed position during whichthe line of action of the spring is transferred from one side to theother side of the visor pivot point and thus biases the visor into theclosed position, the efiect of a subsequent G-force equivalent to thatwhich might be experienced by the wearer on being ejected from hisaircraft by an injection seat being to cause operation through thesecond stage, the lever pivoting so that the line of action of thespring is transferred from one side to the other side of the lever pivotpoint with the result that the lever becomes biased into a positionwhich is such as to cause the visor to be locked in the lower closedposition.

With such a construction of helmet the visor is automatically lockedinto the lower closed position whenever the wearer is subjected to apredetermined G-force, for instance to 126. Due to the use of theG-forces to bring this about, there can be no possibility of itoccurring accidentally or conversely of failure of the visor to belocked at the required instant. Furthermore this construction is suchthat the visor is lowered as well as locked automatically if it shouldbe in the upper open position at the instant of ejection.

The concept of a two stage over-centre mechanism results in aparticularly simple construction of helmet. Few moving par-ts arerequired and those which are can be comparatively simple and do not ingeneral involve close tolerances. Accordingly flying helmets inaccordance with the invention are normally comparatively simple tomanufacture and capable of withstanding rough usage.

By way of example a construction of flying helmet in accordance with theinvention will now be described in more detail with reference to theaccompanying drawings in which:

FIGURE 1 is a diagrammatic side elevation of the complete helmet;

FIGURE 2 is a view corresponding to the front part of FIGURE 1 but to alarger scale and with the canopy and operating mechanism cover removedand showing the visor in the upper open position;

FIGURE 3 is a view corresponding to FIGURE 2 but with the visor in thelower closed position;

FIGURE 4 is a view corresponding to FIGURES 2 and 3 but after operationin response to a G-force so that the visor is locked in the lower closedposition;

FIGURE 5 is a view corresponding to FIGURES 2 to 4 but showing the otherside of the helmet with the visor in the upper open position; and

FIGURE -6 is a sectional view on the line VIVI in FIGURE 2.

Turning first to FIGURE 1, the helmet itself is indicated in generaloutline at 1. A protective visor, part of which is seen at 2, is shownin the upper open position and is pivoted to theside of the helmet at 3.Overlying the visor is a lune-shaped canopy 4 which protects the visorwhen the latter is in the upper open position. The canopy 4 is attachedto a cover 5 for the visor operating mechanism, the latter of which willbe described with reference to FIGURES 2 to 4 and 6. FIGURE 5 shows themechanism on the other side of the helmet which is simpler and will bedescribed later.

Turning first to FIGURE 2, the visor 2, which is tinted to shield thewearers eyes from the sun, includes a pair of side arms 6 (only onevisible) which are pivoted at 3 to each side of the helmet 1. A pin 7 ispivotally journalled about a horizontal axis in the side arm 6 forwardof the visor pivot 3 and carries at the outer end a lever 8 and at theinner end, that is to say the end adjacent the wearers head, a lever 9which is responsive to G-forces and will be referred to as an inertialever. A suitable weight (not shown) may be attached to the lever 9depending on the G-force at which it is to operate.

A tension spring 10 is anchored at one end to an anchorage 11 on thelever 8 and at the other end to an anchorage 12. This latter anchorage12 will be described in detail later but for present purposes, it can beconsidered as being substantially fixed in relation to the helmet 1.

As has already been stated, the visor 2 is in the upper open position inFIGURE 2 into which it is biassed by the spring 10, the lever 8 beingheld against a stop 25. The visor has rearwardly extending projections 2and 28 to the side arms 6. When in the upper open position theprojection 24 is biassed into contact with a rivet 21 secured to theside of the helmet. If the wearer wishes to lower it into the lowerclosed position, he merely pulls it down. As this occurs the levers 8and 9 move with the visor side arms 6 without any relative rotation. Thetension spring 10 pivots about the anchorage point 12 and the line ofaction of the spring is transferred from above the visor pivot 3 tobelow the visor pivot, that is to say to the position shown in FIGURE 3,and the projection 28 contacts the rivet 21. It will be appreciated thatwhen in the latter position, the spring 10 biasses the visor 2 into thelower closed position. However the visor is not locked in this positionand the wearer can move it upwardly into the open position whenever hedesires, movement between the two positions constituting movementthrough the first stage of a two stage over-centre mechanism.

In the event of the wearer being subsequently subjected.

to a sufiicient downward G-force, that is to: say being acceleratedupwardly, the inertia lever 9 turns in a clockwise direction and the pin7 turns in the side arm 6. The G-force required for this to occur mayfor instance be of the order of 10 to 126 and the strength of the spring10 and the moment of inertia of the lever 9 are chosen so that the leverovercomes the former at the correct G-force. As the lever 8 and theinertia lever 9 are both secured to the pin 7, the effect is that thetension spring 10 pivots about the anchorage point 12 and the line ofaction of the spring is transferred from above the axis of the pin 7 tobelow this axis, that is to say moves through the second stage of thetwo stage over-centre mechanism. The parts of the operating mechanismtake up the positions shown in FIG- URE 4 and it can be seen from thisthat the spring 10 now biasses the inertia lever 9 in a clockwise sense.

The inertia lever 9 abuts a pin 13 which is fixed to the helmet 1. Aprojection 14 on the inertia lever 9 fits under the pin 13 and theresult of this is that upward movement of the visor 2 is prevented. Itis clear from FIGURE 4 that such upward movement would result in the pin7 moving upwards and this is prevented by the engagement of theprojection 14 with the pin 13, Thus the visor is locked in the lowerclosed position and as the inertia lever 9 is biased into contact withthe pin 13, the possibility of accidental release is almost entirelyeliminated.

When the emergency is past or if for any other reason, the wearer wishesto raise the visor 2, it is only necessary to pivot the inertia lever 9in an anticlockwise direction so as to release the projection 14 fromthe pin 13. To facilitate this, the inertia lever 9 includes aprojection 15 which can easily be gripped by the wearer.

The lowering of the visor has been described in two stages. However, inthe event of the wearer being ejected from the aircraft when the visoris in the upper, open position, the two stages just described both occurautomatically. Referring to FTGURE 2, the weight of the visor 2 willautomatically cause it to pivot into the closed position and in additionthe inertia lever 9 will pivot in relation to the side arm 6.Accordingly the spring 10 moves through both stages of the over-centremechanism and the visor is automatically lowered and locked into theclosed position.

The anchorage point 12 is in the form of an eyebolt having a screwedshank 16. The shank carries nuts 17 which enable its position inrelation to a lever 18 through which it passes to be adjusted so as toadjust the force exerted by the spring 10. The lever 18 is pivoted at 19to a plate 20 which is riveted to the helmet 1 by the rivet 21. Thelever 18 has an upturned end 22 and as shown in FIGURE 2, this endengages with a pin 23 on a projection 24 of the side arm 6. Thisarrangement constitutes a latch which biasses the visor into the upperopen position. It will be appreciated that downward movement of thevisor necessitates that the lever 22 should pivot in an anticlockwisesense which in turn necessitates that the spring 10 should be extendedslightly. The latch operates in addition to the normal bias provided bythe spring 10 and reduces the possibility of the visor beingaccidentally closed.

Reference to FIGURE shows the other side of the helmet with the coverwhich normally covers the mechanism and the canopy 4 removed. Themechanism includes a tension spring 26 which is anchored at one end toan anchorage 27 attached to the side arm 6. The other end of the spring26 is anchored in the same way as the corresponding end of the spring onthe other side of the helmet and therefore this will not be described,although the corresponding reference numerals are shown for referencepurposes. It is apparent that as shown in FIGURE 5 with the visor in theupper open position the line of action of the spring 26 is above thevisor pivot point 3, as is the line of action of the spring 10 on theother side of the helmet. As the visor is lowered the lines of action ofboth springs are transferred below the pivot points 3. The springs areidentical with one another so that the same bias is applied to the visoron both sides of the helmet.

I claim:

1. A flying helmet fitted with a visor pivoted about a point on saidhelmet and capable of movement between an upper open position and alower closed position, the said helmet including a lever responsive toG-forces pivoted at a point on the said visor about a generallyhorizontal axis, spring means connecting the said lever to the saidhelmet, and automatic locking means between the said helmet and thevisor whereby the said visor can be locked in the lower closed position,the said spring means being anchored at each end at points so located inrelation to the said visor pivot point and the said lever pivot point toconstitute a two stage over-centre mechanism, operation through thefirst stage of the said mechanism being brought about by manual loweringof the said visor into the closed position during which the line ofaction of the said spring means is transferred from one side to theother side of the said visor pivot point thus biassing the said visorinto the closed position, the effect of a subsequent G-force equivalentto that which might be experienced by a wearer of the said helmet onbeing ejected from an aircraft by an ejection seat being to causeoperation through the second stage of the said mechanism, the said leverpivoting so that the line of action of the said spring means istransferred from one side to the other side of the said lever pivotpoint with the result that the said lever becomes biassed into aposition which results in operation of the said locking means to lockthe said visor in the lower closed position.

2. A flying helmet according to claim 1 including a second lever rigidlyconnected to the said pivoted lever and to which one end of the saidspring means is anchored.

3. A flying helmet according to claim 1 in which one of the saidanchorages is adjustable so as to enable the tension of the said springmeans to be adjusted.

4. A flying helmet according to claim 1 in which a second pivoted leveris pivoted to the same helmet and anchored to one end of the said springmeans, the said second pivoted lever engaging with the said visor so asto restrain the visor in the upper open position.

5. A flying helmet fitted with a visor pivoted about a point on saidhelmet and capable of movement between an upper open position and alower closed position, the said helmet including a lever responsive toG-forces pivoted at a point on the said visor about a generallyhorizontal axis, spring means connecting the said lever to the saidhelmet, and automatic locking means comprising a projection on the saidlever and a cooperating projection on the said helmet whereby the saidvisor can be locked in the lower closed position, the said spring meansbeing anchored at each end at points so located in relation to the saidvisor pivot point and the said lever pivot point as to constitute to atwo stage over-centre mechanism, operation through the first stage ofthe said mechanism being brought about by manual lowering of the saidvisor into the closed position during which the line of action of thesaid spring means is transferred from one side to the other side of theside visor pivot point thus biassing the said visor into the closedposition, the effect of a subsequent G-force equivalent to that whichmight be experienced by a wearer of the said helmet on being ejectedfrom an aircraft by an ejection seat being to cause operation throughthe second stage of the said mechanism, the said lever pivoting so thatthe line of action of the said spring means is transferred from one sideto the other side of the said lever pivot point with the result that thesaid lever becomes biassed into a position which results in operation ofthe said locking means to lock the said visor in the lower closedposition.

References Cited UNITED STATES PATENTS 3,128,469 4/1964 Lobelle 263,239,843 3/1966 Lobelle 26 FOREIGN PATENTS 951,817 3/1964 GreatBritain.

HERBERT F. ROSS, Primary Examiner.

5. A FLYING HELMET FITTED WITH A VISOR PIVOTED ABOUT A POINT ON SAIDHELMET AND CAPABLE OF MOVEMENT BETWEEN AN UPPER OPEN POSITION AND ALOWER CLOSED POSITION, THE SAID HELMET INCLUDING A LEVER RESPONSIVE TOG-FORCES PIVOTED AT A POINT ON THE SAID VISOR ABOUT A GENERALLYHORIZONTAL AXIS, SPRING MEANS CONNECTING THE SAID LEVER TO THE SAIDHELMET, AND AUTOMATIC LOCKING MEANS COMPRISING A PROJECTION ON THE SAIDLEVER AND A COOPERATING PROJECTION ON THE SAID HELMET WHEREBY THE SAIDVISOR CAN BE LOCKED IN THE LOWER CLOSED POSITION, THE SAID SPRING MEANSBEING ANCHORED AT EACH END AT POINTS SO LOCATED IN RELATION TO THE SAIDVISOR PIVOT POINT AND THE SAID LEVER PIVOT POINT AS TO CONSTITUTE TO ATWO STAGE OVER-CENTER MECHANISM, OPERATION THROUGH THE FIRST STAGE OFTHE SAID MECHANISM BEING BROUGHT ABOUT BY MANUAL LOWERING OF THE SAIDVISOR INTO THE CLOSED POSITION DURING WHICH THE LINE OF ACTION OF THESAID SPRING MEANS IS TRANSFERRED FROM ONE SIDE TO THE OTHER SIDE OF THESIDE VISOR PIVOT POINT THUS BIASSING THE SAID VISOR INTO THE CLOSEDPOSITION, THE EFFECT OF A SUBSEQUENT G-FORCE EQUIVALENT TO THAT WHICHMIGHT BE EXPERIENCED BY A WEARER OF THE SAID HELMET ON BEING EJECTEDFROM AN AIRCRAFT BY AN EJECTION SEAT BEING TO CAUSE OPERATION THROUGHTHE SECOND STAGE OF THE SAID MECHANISM, THE SAID LEVER PIVOTING SO THATTHE LINE OF ACTION OF THE SAID SPRING MEANS IS TRANSFERRED FROM ONE SIDETO THE OTHER SIDE OF THE SAID LEVER PIVOT POINT WITH THE RESULT THAT THESAID LEVER BECOMES BIASSED INTO A POSITION WHICH RESULTS IN OPERATIONSOF THE SAID LOCKING MEANS TO LOCK THE SAID VISOR IN THE LOWER CLOSEDPOSITION.